JPH1145453A - Optical pickup - Google Patents

Abstract

(57) [Problem] To provide an optical pickup that is miniaturized, reduced in cost, and has high reliability while suppressing the use of a flexible flat cable as much as possible. SOLUTION: A laser coupler 21 encapsulating a semiconductor laser 23, a prism 24, and a photodetector is fixed, and supports a biaxial movable unit 13 to which an objective lens 28, a focusing moving coil 17, and a tracking moving coil are attached. The base 1 to be formed is a molded product of a synthetic resin, and power is supplied to the laser coupler 21, the focusing moving coil 17 and the tracking moving coil by a thin-film electric circuit 32 formed on a three-dimensional surface of the base 1, 33, 34a and 34b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup for reproducing an information signal recorded on an optical information recording medium, and more particularly, to a three-dimensional electric circuit on a base (body) of the optical pickup. The present invention relates to an optical pickup in which is formed.

[0002]

2. Description of the Related Art An optical pickup for reproducing an information signal recorded on an optical information recording medium such as an optical disk or a magneto-optical disk includes a CD (compact disk) player, a VD (video disk), and an MD.
(Minidisc), various CD-ROM (Seed ROM) players, as well as game machines, are expanding their applications.

An optical pickup, for example, scans a signal recording surface of an optical disk in a radial direction, squeezes a light beam emitted from a semiconductor laser by an objective lens, irradiates the signal recording surface of the optical disk with a light beam, and receives a reflected light beam by a photodetector. However, the optical pickup has a large number of parts, and the assembly work is complicated and costly. In addition, there is a great demand for downsizing the optical pickup.

FIG. 6 is an exploded perspective view of a conventional optical pickup 100. FIG. In the optical pickup 100, a bent magnetic metal plate 111 is fixed on a base (main body) 101, and a support member 115 fixed to the bent magnetic metal plate 111 is provided.
A biaxial movable portion 113 is supported at a tip end of a metal leaf spring 116 attached to the metal plate spring 116. Also, the biaxial movable part 11
An objective lens 128 is attached to 3. The inside of the focusing moving coil 117 that is attached to the two-axis movable part 113 and moves the two-axis movable part 113 in the vertical direction is attached to the bent part (yoke) 111A of the bent magnetic metal plate 111 and to it. The magnet 112 is loosely inserted, and the other bent portion (yoke) 11 is inserted.
A hole 119 provided in the biaxial movable portion 113 is loosely inserted between the focusing moving coil 117 and the objective lens 127 to form a magnetic circuit with the magnet 112. Although not shown, a tracking moving coil that moves the biaxial movable portion 113 in the direction indicated by the arrow m is attached to the side surface of the focusing moving coil 117 on the bent portion 111B side.
The cover 10 provided with the window 108 for the laser beam
9 is attached to the base 101 so as to cover the support member 115 and the biaxial movable portion 113.

Further, a laser coupler 121 is attached to a lower end of a rectangular tube-shaped laser coupler attaching portion 102 provided on the lower surface side of the base 101. The upwardly directed laser beam from the semiconductor laser in the laser coupler 121 is applied to the optical path hole 10 formed in the base 101.
3, the beam is squeezed by an objective lens 128 and irradiates a signal recording surface of an optical disk (not shown), and the reflected light flux passes through the objective lens 128 again and returns to the photodetector in the laser coupler 121, where an information signal and a focus signal are focused. An error signal and a tracking error signal are read.

The base 101 has a sub shaft 147 fitted in a main shaft 145 of the chassis through which the two main bearings 104 at one end are inserted and a sub bearing 105 at the other end in a chassis (not shown). And the arrow m
The optical disk is reciprocated in the direction shown by the arrow and scans the signal recording surface of the optical disk. A board 141 of a flexible flat cable (hereinafter abbreviated as an FF cable) is attached to the chassis.
Is connected to the supporting member 115 for supplying power to the focusing moving coil 117 and the tracking moving coil attached to the biaxial movable portion 113, and the other end of the FF cable 143 is connected to the laser coupler 121. It is connected to the bottom side for power supply.
The board 141 of the FF cable is connected to external wiring via a connector 144.

FIG. 7 is an enlarged perspective view showing the support member 115 and the biaxial movable portion 113 described above. Biaxial movable part 1
The metal leaf springs 13 are supported on both sides by the distal ends of four metal leaf springs 116 integrally attached to the support member 115, and protrude to the rear side of the support member 115.
6 at the end 116e of the FF cable 142 in the end 116e.
2h is fitted and fixed to the support member 115 with solder. As described above, the two-wheel movable unit 113
Is provided with an objective lens 128, a focusing moving coil 117, and a tracking moving coil, and a hole 119 is formed in the middle of the hole 119 into which the bent portion 111B of the magnetic metal plate 117 is loosely inserted.

[0008]

The conventional optical pickup 100 is configured as described above. The FF cable 1 is used to supply power to the focusing moving coil 117, the tracking moving coil, and the laser coupler 121.
However, the use of the FF cable increases the number of parts including the parts for attaching the FF cable, and the work of attaching the FF cable requires a work of attaching the FF cable. there were. In addition, it is difficult to cope with the future complexity and miniaturization of the shape of the base when using FF cables frequently, and the connection that bends the FF cables in a complicated manner may break due to long-term use. The problem is also inherent.

The present invention has been made in view of the above-described problems, and has been developed in consideration of the FF
It is an object of the present invention to provide a miniaturized, low-cost, and highly reliable optical pickup by minimizing the use of cables.

Japanese Patent Application Laid-Open No. 6-28941 discloses an illuminated switch device and a method of manufacturing the same as a prior art for reducing the number of components and the size of components for electronic devices. Regarding the operation switch of a small device such as a mobile phone or a small VTR camera, on the surface of a package as a synthetic resin molded product in which an electric contact and a light emitting element for display are mounted adjacent to each other, both electrodes serving as electric contacts and A light emitting element in which a wiring portion of a display light emitting element is formed by a technique such as chemical plating is disclosed. Also, Japanese Patent Application Laid-Open No. 6-37
The “light emitting device” according to Japanese Patent Publication No. 359 includes a light emitting device for surface mounting used in a copying machine, a laser printer, or the like, in which a metal wiring electrode portion is chemically mounted on a package as a synthetic resin molded product on which a light emitting element is mounted. One formed by a method such as plating is disclosed. These are all three-dimensional circuit molded parts, so-called MID (Molded Inter).
connect device), but has nothing to do with the optical pickup of the present invention. In addition, JP-A-9
Japanese Patent Publication No. 7716 discloses an electrical connector for easily connecting a circuit conductor of a three-dimensional circuit molded part (MID) to an external wiring.

[0011]

The above object is achieved by the present invention. An optical pickup according to the present invention comprises a semiconductor laser for emitting a laser beam and an information beam by narrowing a light beam emitted from the semiconductor laser. An objective lens that irradiates a recording medium and passes a reflected light beam from an information recording medium, a photodetector that detects an information signal, a focus error signal, and a tracking error signal from the reflected light beam, and an objective lens that emits a light beam from a semiconductor laser. And a prism or equivalent optical component for guiding the reflected light flux reflected from the information recording medium and passing through the objective lens to the photodetector, and the semiconductor moved with respect to the main body moved in the radial direction of the information recording medium. A laser, prism or equivalent optics, and a photodetector are mounted as encapsulation components, and the objective lens is The main body is made of synthetic resin in an optical pickup mounted so that its position can be adjusted in two axes, vertical and horizontal, by the current flowing through the corresponding moving coil for focusing and the moving coil for tracking based on the tracking error signal. And a thin-film electric circuit formed on a three-dimensional surface of the molded product to supply power to the sealing component and the moving coil for focusing and the moving coil for tracking. .

By using such an optical pickup, the FF cable used for power supply in the conventional example becomes unnecessary, the required space is reduced, and the size and thickness can be reduced. And the reliability is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical pickup according to an embodiment of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows an optical pickup 10 according to the present embodiment.
FIG. 3 is an exploded perspective view of FIG. The base (main body) 1 is a molded product formed by injection molding with a synthetic resin, and has a main bearing 4 and a sub bearing 5 at both ends in the longitudinal direction thereof. And is guided to the counter shaft and reciprocated in the direction indicated by the arrow n. The laser coupler 21 is attached to the recess 2 of the base 1 on the side of the sub-bearing 5 and is sealed by a glass plate 26 with a mirror 25. On the other hand, on the main bearing 4 side, a support member 15 made of synthetic resin is attached to a magnetic metal plate (not shown) fixed on the base 1.
Is fixed, and the biaxial movable portion 13 made of synthetic resin is vertically and arrow-headed by four metal leaf springs 16 (all not shown) integrally attached to the support member 15. It is supported on both sides so that it can move in the direction shown. In FIG. 1, the cover of the biaxial movable portion 13 is omitted.

FIG. 2 is an enlarged perspective view showing the support member 15 and the biaxial movable portion 13, and corresponds to FIG. 7 of the conventional example.
That is, the biaxial movable portion 13 includes four metal leaf springs 16a, 16b, 1 that are integrally attached to the support member 15.
6c and 16d, and are supported by the support members 15
The metal leaf springs 16 a ′ and 16 b ′ at the base end that are pulled out from the two-axis movable part 13 on the surface side of the base 1, and the metal spring 16 at the base end as well.
c 'and 16d' are soldered to an electric circuit to be described later on the back surface side of the base 1, respectively. In addition, the metal leaf spring 16a,
16b, 16c and 16d are support members 1 made of synthetic resin
5 and the two-axis movable portion 13 also made of synthetic resin, which are integrally molded by, for example, insert molding, so that the mounting operation is unnecessary and the production cost is reduced. Also, four metal leaf springs 16a, 16b, 16c, 16d
By supporting the two-axis movable portion 13 in two steps, an effect that the biaxial movable portion 13 is less likely to be twisted is obtained.

An objective lens 28 and a moving coil for focusing 17 are attached to the tip of the biaxial movable part 13, and a bent part 11 of a magnetic metal plate is provided between the two.
A hole 19 into which B is inserted is formed.

Returning to FIG. 1, the magnet 12 is loosely inserted into the focusing moving coil 17 of the biaxial movable portion 13 together with the one bent portion 11A of the magnetic metal plate, and the other bent portion 11B of the magnetic metal plate. Is a biaxial movable unit 1 between the objective lens 28 and the focusing moving coil 17.
3 is loosely inserted into the hole 19 formed in the magnet 1.
2, a magnetic circuit is formed. Although not shown, a tracking moving coil for moving the biaxial movable portion 13 in the direction indicated by the arrow n is attached to the side surface of the focusing moving coil 17 on the bent portion 11B side. The four metal leaf springs 16a, 16
The distal ends of b, 16c, and 16d are inserted into the biaxial movable portion 13. For example, the distal ends of the metal leaf springs 16a and 16b are connected to the focusing moving coil 17, and the distal ends of the metal leaf springs 16c and 16d are It is connected to a tracking moving coil and is also used as a power supply circuit.

These structures are the same as those of the conventional example. Then, a current flows through the focusing moving coil 17 and the tracking moving coil based on the focus error signal and the tracking error signal read together with the information signal by the laser coupler 21,
The two-axis movable section 13 is moved in the vertical direction and the direction indicated by the arrow n to adjust the position of the objective lens 28, and the focus error and the tracking error are corrected.

FIG. 3 shows the laser coupler 21 shown in FIG.
FIG. 5 is an enlarged perspective view of a recess 2 in which
FIG. 2 is a schematic diagram showing a positional relationship between a laser coupler 21, an objective lens 28, and an optical disk 29 as an information recording medium. The laser coupler 21 has a semiconductor laser 23 and a prism 24 mounted on a substrate 22.
A photodetector is formed on the lower substrate 22 (not shown). The laser beam emitted from the semiconductor laser 23 is reflected upward by the prism 24 and is bent by the mirror 25. Then, the light passes through the optical path hole 3 formed in the recess 2, reaches the rising mirror 27, is raised, is squeezed by the objective lens 28, and irradiates the information recording surface of the optical disk 29. The reflected light beam of the laser returns to the same optical path, but is guided to the photodetector by the prism 24, and the information signal, the focus error signal, and the tracking error signal are read.

In FIG. 1, power is supplied to the laser coupler 21 and the focusing moving coil 17 and the tracking moving coil of the two-axis movable portion 13 by the base 1 as a synthetic resin molded product and the side surface of the base 1. At the same time, the three-dimensional surfaces of the plate-shaped electric connection fitting portions 8 formed by chemical plating are chemically plated to form thin-film electric circuits 32, 33 formed in a predetermined pattern.
34a, 34b, etc., and the electrode 31. Substrate 22, semiconductor laser 23 and electric circuit 3
2, 33 are electrically connected, for example, by wire bonding or the like. That is, the electric circuit 32 connected to the right side of the laser coupler 21 from the plurality of electrodes 31 of the electric connection fitting 8, and the laser coupler 21 from the electric connection fitting 8 via the back surface of the base 1. In addition to the plurality of electric circuits 33 connected to the left side, for example, the electric circuit 34 to the focusing moving coil 17
a and 34b are routed from the back side of the base 1 to the front surface of the base 1 on both sides of the two-axis movable portion 13, and two ends of the upper two supporting the two-axis movable portion 13 are provided at their ends. Metal plate springs 16a and 16b are soldered. As described above, power is supplied to the focusing moving coil 17 via the metal springs 16a and 16b. A similar electric circuit is formed on the back side of the base 1 for the moving coil for tracking, and power is supplied through the lower two metal springs 16c and 16d supporting the biaxial movable portion 13. You. That is, the optical pickup 10 is a three-dimensional circuit molded component, so-called MID
It is manufactured as. Further, the external wiring and the FF cable 42 are connected to the electrode 31 of the electrical connection fitting portion 8.
By connecting and fitting a connector 41 having a connection electrode formed therein (not shown).
The optical pickup 10 is easily and reliably connected to external wiring.

The optical pickup 10 according to the embodiment is configured as described above. Next, the operation thereof will be described.

As described above, the optical pickup 10 is formed as a three-dimensional circuit molded part, and the optical pickup 100 of the conventional example is an FF cable 14 as a power supply circuit.
2 and 143 need space to be bent as the base 101 reciprocates, whereas the optical pickup 1
0, a thin-film three-dimensional electric circuit 32, 3
The space occupied by 3, 34a, 34b and the like is so small as to be incomparable, and further, the shape of the base 1 itself is changed, so that the optical pickup 10 is greatly reduced in size and thickness. Further, since the FF cables are not used in the optical pickup 10, the number of parts including the parts for attaching them is reduced, and the operation of attaching and connecting them, which is difficult to automate, becomes unnecessary, so that the manufacturing cost is greatly reduced. In addition to the reduction, the possibility of disconnection of the FF cable is also eliminated, and the reliability is improved.

The biaxial movable unit 13 is supported by a power supply circuit for the focusing moving coil 17 and the tracking moving coil for moving the biaxial movable unit 13 to which the objective lens 28 is attached in the vertical and horizontal directions. The number of parts is reduced by also using the metal leaf springs 16a, 16b, 16c, and 16d.
b, 16c, 16d by the support member 15 and the biaxial movable part 1
3, and the cost is reduced also in these aspects.

Further, the base 1 which is a synthetic resin molded product
Electric circuits 32, 33, 3 formed on the three-dimensional surface of
The connection between 4a, 34b and the like and the external wiring is performed by forming the connector 41 at the same time as the base 1 and fitting the connector 41 to the electrical connection fitting portion 8 on which the electrode 31 is formed by chemical plating. This eliminates the need for soldering to the external wiring, and significantly improves the reliability of connection with the external wiring.

The optical pickup 10 according to the present embodiment is constructed and operates as described above. However, it goes without saying that the present invention is not limited to this, and various modifications are possible based on the technical idea of the present invention. .

For example, in the present embodiment, the base 1 which is a synthetic resin molded product of the optical pickup 10 may be formed by injection molding alone, but as shown in the perspective view of FIG. It may be injection molded with a mold. That is, FIG. 5 shows the two bases 1 and 1 ′ which are formed upward, and together with the frame 6 at the time of molding, the base 1 is connected by the connecting parts 7 a and 7 b, and the connecting parts 7 a ′ and 7 ′ are formed.
The base 1 'is simultaneously formed by b'.
Of course, three or more pieces may be molded simultaneously. By using a plurality of bases, the manufacturing cost per base can be reduced, and the work efficiency can be improved by mounting the laser coupler 21, for example, with the frame 6 as shown in FIG. Is also possible. Further, although injection molding is employed in the present embodiment, transfer molding may be employed.

In the present embodiment, the base 1,
Although the recesses 2, the electric circuits 32, 33, 34a, 34b, etc. on the three-dimensional surface of the electric connection fitting 8 and the electrodes 31 are formed by chemical plating, a method other than chemical plating, for example, It may be formed by vacuum evaporation or sputtering. It goes without saying that, after chemical plating, ordinary electrolytic plating may be overlaid thereon.

Further, in the present embodiment, four metal leaf springs are employed as metal springs integrally attached to a support member 15 for supporting the biaxial movable portion 13 for adjusting the position of the objective lens. However, it is needless to say that these may be four metal wires such as a piano wire or a coil spring may be used.

Further, in the present embodiment, the fitting portion 8 for electric connection has a plate shape, but may have another shape, for example, a columnar shape.

In the present embodiment, a laser coupler 21 in which a semiconductor laser 23 is combined with an optical prism 24 for reading an information signal from an optical disk 29 is used.
Is used, but a diffraction grating can be used instead of the prism 24. For a magneto-optical disk, a prism for the magneto-optical disk is used.

In this embodiment, the synthetic resin used for molding the base 1 is not specified.
Depending on the mechanical strength, electrical insulation, heat resistance, flame retardancy, etc. expected of the optical pickup 10, heat molding is possible with synthetic resins such as polyoxymethylene, polycarbonate, polyphenylene sulfide, and other engineering plastics. Is appropriately selected from the following.

In this embodiment, the material of the thin-film electric circuits 32, 33, 34a, 34b or the electrodes 31 of the electric connection fitting portion 8 is not specified, but, for example, nickel, copper, gold or the like is used. Can be adopted.

[0033]

The optical pickup of the present invention is embodied in the above-described embodiment, and has the following effects.

In the optical pickup of the present invention, the power supply to the focusing moving coil and the tracking moving coil for adjusting the positions of the semiconductor laser, the prism, the photodetector, and the position of the objective lens is performed by molding a synthetic resin. This is done by a thin-film electric circuit formed on the three-dimensional surface of the product, so the conventional example eliminates the need for a flexible flat cable that is directly connected to the sealing component and both moving coils. The size and cost of the pickup can be reduced, and the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an optical pickup according to an embodiment.

FIG. 2 is a perspective view of a support member and a biaxial movable portion attached to the optical pickup.

FIG. 3 is a perspective view of a laser coupler attached to the optical pickup.

FIG. 4 is a schematic diagram showing a positional relationship among a laser coupler, an objective lens, and an optical disk.

FIG. 5 is a perspective view showing a main body of a molded article made of a synthetic resin molded by a two-piece mold.

FIG. 6 is an exploded perspective view of a conventional optical pickup.

FIG. 7 is a perspective view of a support member and a biaxial movable portion attached to a conventional optical pickup.

[Explanation of symbols]

1 ... base (body), 8 ... fitting part for electrical connection, 10
... Optical pickup, 13 Biaxial movable part, 15 Support member, 16a, 16b, 16c, 16d Metal leaf spring, 17 Moving coil for focusing, 21
Laser coupler, 23 ... Semiconductor laser, 24 ...
Prism, 28 ... objective lens, 31 ... electrode, 32,
33, 34a, 34b ... electric circuit

Claims (6)

[Claims] 1. A semiconductor laser that emits a laser beam, an objective lens that narrows an emitted light beam from the semiconductor laser and irradiates the information recording medium with the light beam, and passes a reflected light beam from the information recording medium; Information signal,
A light detector for detecting a focus error signal and a tracking error signal; and a prism or an equivalent optical component for guiding the emitted light beam toward the objective lens and guiding the reflected light beam to the light detector. For the body that is moved in the radial direction of the medium,
The semiconductor laser, the prism or equivalent optical component, and the photodetector are mounted as a sealing component, and the objective lens has a corresponding moving coil for focusing and tracking based on the focus error signal and the tracking error signal. An optical pickup mounted so as to be position-adjustable in two axial directions of a vertical direction and a horizontal direction by a current flowing through a moving coil for use, wherein the main body is a molded product made of synthetic resin, and the three-dimensional An optical pickup, wherein a thin-film electric circuit is formed on a surface, and power is supplied to the sealing component, the focusing moving coil, and the tracking moving coil by the electric circuit. 2. A two-axis movable part to which the objective lens, the focusing moving coil, and the tracking moving coil are attached is supported by a distal end of a metal spring integrally attached to a support member on the molded product. The power supply to the moving coil for focusing and the moving coil for tracking is performed via the metal spring connected to the electric circuit on the molded product. Optical pickup as described. 3. The apparatus according to claim 2, wherein the metal spring comprises four springs, and two of the springs are also used to supply power to the focusing moving coil and the tracking moving coil. Optical pickup as described. 4. A connection between the electric circuit and the external wiring on the molded product, wherein the protrusion-shaped fitting portion integrally formed with the molded product and having an electrode connected to the electric circuit; The optical pickup according to any one of claims 1 to 3, wherein the connection is performed by fitting a connector having an electrode connected to the wiring. 5. The support member and the two-axis movable portion are formed of a synthetic resin, and the metal spring is formed integrally with at least one of the support member and the two-axis movable portion. The optical pickup according to claim 4, wherein: 6. The optical pickup according to claim 5, wherein said molded article made of a synthetic resin is molded by a plurality of molds at the time of molding.